Okay then,
I had great luck with my mortar, my brick cutting and laying up the first seven chains. Then came number eight.

You guys don't talk much about that point at which the angle is so steep you have to hold the bricks in place while you are mortaring them up.

... or the back pain associated with bending over a huge half sphere trying to hold a brick in place that is covered with sticky mortar while grabbing something to lean against it.

Yes, it's true, I am not the pristine oven builder that most here seem to be, dang! I would love it to work out perfect, and I want my arches to be almost self supporting ( no real work done by the mortar) but when I smear them with mortar, I usually have to get out the rubber mallet to persuade those wedges into a reasonable arch.

Anyway, after one last chain of ( not so easy) leaning 1/2 bricks, I was faced with the choice of going to 1/4 bricks, 1/3 bricks, or just arching over the top left to right, then maybe again front to back, and ending up with a sort of series of spans up there, and 4 last holes to plug with a triangle piece.

Tonight I tried both options and chose the latter. Arching across the top with about 5 1/2 brick wedges. After one somewhat successful one in the middle, I went ahead and made an arch on either side of that, and it was MUCH easier that cutting bricks into 3 or four pieces and trying to taper them at the same time.

Thoughts?

For my arches, I figured, ( I mean across the top of the dome) even if they aren't perfect, the inside will be rarely if ever seen, and the outside will be completely covered with insulation. I probably have some mortar voids, and that may be a concern... I don't know enough about how this mortar acts over many years and many firings.

... I have seen both ways ... smaller bricks in the top chains, and arching across... what did you do ( those who have finished)

( my progress can be seen in my photo album on my profile page)

For all my arches so far, I have just used a 2 1/2" strip of either 1/8" tile board, or 1/4" masonite and clamped on either side of the dome edge with a 'quick grip'. It works SO easily, and the tapered angle ( for my 39" inside diameter oven) of 4" and 5" follow the curve pretty exactly. ( Okay, most of your 'exactly' standards may force me to reword that...) But, if I were using a saw, it would be an absolute snap to get these arches VERY close with this extremely quick and easy technique.

Lars,
an easy way to complete the last few chains is to stack some bricks on the inside of the oven end on and put a false plywood floor at the top of your last chain, but make sure it will come out through your opening. Get some moist sand (but not wet nor need to put portland cement in it) and form a slightly packed dome which you can then sit your bricks on to hold in place till mortar is set. You can easily make a smallish contour to shape it accurately to fit your oven radius
Get the whole lot done quickly so that as soon as you have put in your finasl keystones, you can pull out the form work, crawl/slide inside and clean/adjust the bricks that need the final adjustment outwards. There isn't much room nor light in there when your gut closes the oven arched entry so put a light in there to see what you are doing beforehand. I hope you are not clostrophobic as there isn't much room available to move and swing your arms. Hopefully, it will be the only time when you venture into your oven..
I found my back ached something chronically, until I spread my legs as far as comfortable and support your upper torso with your knees on the already completed and set courses.

Hi Rastys,
Thanks for the ideas. I did stack some blocks in there for the last chain I put up, and just set house bricks up against the chain members as I mortared them in, but it was still back breaking.

That is why I decided to over arch. It will not be perfect, that's for sure, but there is hardly any working inside the oven chamber when you can clamp a flexible piece of wood to each side and hold up the span. I unclamp the support after the last piece is mortared.

If I had electricity at my site, I would most definitely be cutting more precise wedges... but for now, a chisel is all I am using, and the arch pieces are hanging in place even before any mortar, for the most part.

Well,
After talking to two clay pottery guys, and a glass blower, I am ready do finish my oven top with a very arching approach, and there will not be a smooth rounded interior, exactly, and the there will be some thick mortar joints.

Without the tile saw, my chisel and rubbing the bricks against the concrete blocks to smooth them out a bit, I can get the whole top filled in and stable whether the mortar holds or not.

I asked the kiln makers what the nature of the fire clay properties would be after firing the oven and from what they said, I am pretty sure my method will last a long time.

With all the discussion of 'curing' the oven, I have really not seen any posts that talk about what actually happens when the portland burns out and the clay starts to solidify. I was told, that at around 1000 degrees, the fireclay content of my mortar will take on more water resistant and harder properties ( which is what might compromise an outdoor oven over the years, I would think)

Live and learn, right? ( hopefully) I know that most of you are going to hate this oven top... and I hesitate to post it for all to see how badly my bricks are fitting. Worst case, I have to re-build it with the smooth inside dome at some later date.

Lars, well first of all, I have to say your upper half in pic 2 does not look at all like your bottom half in pic 3... but that's neither here nor there...

Your solution to spanning and closing your dome is great. I really love it. I would not have the guts to do that but I'm really impressed you did. It's weird, I had no problem with the upper bricks, they held well and slipped just enough were my last 3 courses look like steps but my oven cooks the pizzas (2 days worth so far) just perfect. I know yours will too. PLEASE take a pic of the inside of the dome for us. This kind of brick detail with chisel and brick rubbing is really impressive. I love your arch and keystone. I think our ovens should be reflections of our personalities not just perfect cooking machines and I know mine is and yours is just fine.

Oh, and I can really commiserate with you and back up your claim: All the pilates and ab-core classes I've taken are nothing compared to leaning over a 3 and half foot dome fastening bricks at arms length for days. Interesting what people leave out in this forum for us discover ourselves. Enjoy the ride and again, your ovens looks quite fine, please keep up the pics, -Dino

Lars,
you now have 4 lots of keystones to cut to fill your 4 corners, but so be it. It will still be fine and hold together.
I agree totally with Dino but I think that the young lady is your apprentice or off sider, eh? You obviously are not working her enough as she is too clean for a brickies apprentice.
A pity you didn't get her young and flexible back to do the 'hard parts' for you. Just imagine standing back and giving advice rather than demonstrations.
Anyway, good job and it will cook your pizzas a treat.

Well, on an unrelated note, I just spent the night in the emergency room -- kidney stone. So, I guess mortar and stone really is a part of me!

I had planned to go out with my youngest today and mortar in most of those VERY frustrating triangular/curved fill areas.

Thank- you for the encouragement, and I will add a snapshot of the inside (against my better judgment)... actually after looking, I will have to take one later when I can show the whole inside dome.

There are some areas where dome meets arch ( the opening) where I filled in with mortar. If those pieces fall out after the oven is cured, then I will get some of the real high test mortar, repair it, and fire it in the same day and that might work, but I am just learning here, and dont really have first hand experience with how this stuff works.

Oh, one other thing. While researching the mortar, and how it will, in theory, work after firing, I watched a glass guy ( artist) make a piece of artglass ( just while we were talking) and those furnaces are going 24/7 because they take a week to get up to temp --up to 400 lbs of molten glass in the bottom of the furnace! It was really cool ( actually the opposite!)

Actually, while laying on my back smoothing and stuffing voids, scraping off brick faces a bit, I was pretty happy. There are many joints that are pretty thin, and all the way through. Here's the pictures.

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